Ananda, the Buddha's disciple, while on a mission for the Buddha, requested water to drink from a woman of low cast. The woman protested out of fear that her low caste would contaminate Ananda's holiness; to which Ananada replied, "I ask not for caste but for water." A version of the Buddhist text of this story is available here: http://www.mountainman.com.au/buddha/carus_76.htm